Processes for treating halogen-containing gases

Abstract

There are disclosed various processes, apparatuses and systems for treating a halogen-containing gas such as F 2 that involve generating a plasma in order to reduce chemically the halogen-containing gas into products that are more environmentally manageable. According to a particular embodiment, a reducing agent is mixed with the halogen-containing gas to produce a feed gas mixture and a non-thermal plasma is generated in the feed gas mixture in the presence of liquid water. According to another embodiment, a vaporized portion of a liquid reducing agent is mixed with the halogen-containing gas to produce a reaction mixture and a non-thermal plasma is generated in the reaction gas mixture to reduce the halogen-containing gas.

1. A process for treating a halogen-containing gas, comprising:
 introducing a halogen-containing gas into a reactor; 
 introducing a liquid reducing agent into the reactor; 
 vaporizing a portion of the liquid reducing agent in the reactor; 
 generating a non-thermal plasma in the reactor in the presence of a non-vaporized portion of the liquid reducing agent to reduce the halogen-containing gas; and 
 removing the resulting reduction product from the reactor, wherein the non-vaporized portion of the liquid reducing agent forms a liquid region with a liquid surface facing an interior of the reactor. 
 
     
     
       2. The process according to  claim 1 , wherein the non-vaporized portion of the liquid reducing agent flows through the reactor during generation of the non-thermal plasma. 
     
     
       3. The process according to  claim 1 , wherein the liquid reducing agent is selected from water, a high vapor pressure hydrocarbon, an olefin, or a reducing agent dissolved in a liquid carrier. 
     
     
       4. The process according to  claim 3 , wherein the liquid reducing agent comprises water. 
     
     
       5. The process according to  claim 1 , wherein the vaporizing of a portion of the liquid reducing agent is effected by the liquid reducing agent absorbing heat produced by the reduction of the halogen-containing gas. 
     
     
       6. The process according to  claim 1 , wherein the non-thermal plasma comprises a silent discharge plasma. 
     
     
       7. The process according to  claim 2 , wherein the resulting reduction product comprises at least one water-soluble halogen-containing substance, and the removing of the resulting reduction product from the reactor comprises dissolving the water-soluble halogen-containing substance in the non-vaporized portion of the liquid reducing agent and discharging the resulting solution from the reactor. 
     
     
       8. A continuous process for treating a halogen-containing gas, comprising:
 providing a reactor defining at least one gas inlet for receiving a halogen-containing gas, and at least one inlet for receiving a liquid reducing agent; 
 providing at least one first electrode and at least one second electrode disposed within the reactor; 
 flowing the liquid reducing agent over at least a portion of the first electrode; 
 vaporizing a portion of the liquid reducing agent in the reactor; and 
 applying electric potential to at least one of the first electrode or the second electrode so as to generate a plasma that reduces the halogen-containing gas in the continuous presence of a non-vaporized portion of the liquid reducing agent. 
 
     
     
       9. The process according to  claim 8 , wherein a dielectric barrier is disposed on a surface of the first electrode, and the generated plasma comprises a non-thermal plasma. 
     
     
       10. The process according to  claim 8 , wherein the liquid reducing agent is selected from water, a high vapor pressure hydrocarbon, an olefin, or a reducing agent dissolved in a liquid carrier. 
     
     
       11. The process according to  claim 8 , wherein reducing the halogen-containing gas produces a reaction product mixture that includes a water-soluble halogen-containing reduction product, the process further comprising separating the water-soluble halogen-containing reduction product from the reaction product mixture. 
     
     
       12. The process according to  claim 11 , wherein the separating comprises aqueous scrubbing. 
     
     
       13. The process according to  claim 11 , the process further comprising dissolving the water-soluble halogen-containing reduction product into the liquid reducing agent. 
     
     
       14. The process according to  claim 13 , further comprising adding at least calcium hydroxide or sodium hydroxide to the liquid reducing agent. 
     
     
       15. The process according to  claim 7 , further comprising adding at least calcium hydroxide or sodium hydroxide to the liquid reducing agent. 
     
     
       16. A process for treating F 2  gas, comprising:
 introducing F 2  gas into a chamber; 
 introducing a liquid reducing agent into the chamber; 
 vaporizing a portion of the liquid reducing agent in the chamber; 
 generating a non-thermal plasma in the chamber in the presence of a non-vaporized portion of the liquid reducing agent to reduce the F 2  gas into hydrogen fluoride; and 
 removing the resulting hydrogen fluoride from the chamber, wherein the non-vaporized portion of the liquid reducing agent forms a liquid region with a liquid surface facing an interior of the chamber. 
 
     
     
       17. The process according to  claim 16 , wherein the non-vaporized portion of the liquid reducing agent flows through the chamber during generation of the non-thermal plasma. 
     
     
       18. The process according to  claim 16 , wherein the liquid reducing agent is selected from water, a high vapor pressure hydrocarbon, an olefin, or a reducing agent dissolved in a liquid carrier. 
     
     
       19. The process according to  claim 18 , wherein the liquid reducing agent is water. 
     
     
       20. The process according to  claim 16 , wherein the vaporizing of a portion of the liquid reducing agent is effected by the liquid reducing agent absorbing heat produced by the reduction of the F 2  gas. 
     
     
       21. The process according to  claim 1 , wherein the non-thermal plasma is generated at a temperature less than or equal to about 100° C. 
     
     
       22. The process according to  claim 1 , wherein the liquid region is contiguous with an inner surface of the reactor.